Re: [patch 1/2] KVM: x86: handle double and triple faults for every exception

[Avi Kivity <avi@redhat.com>]

On 11/12/2009 02:26 PM, Gleb Natapov wrote:
>>
>> -	if (vcpu->arch.exception.pending) {
>> -		switch(vcpu->arch.exception.nr) {
>> -		case DF_VECTOR:
>> -			/* triple fault ->  shutdown */
>> -			set_bit(KVM_REQ_TRIPLE_FAULT,&vcpu->requests);
>> -			return;
>> -		case PF_VECTOR:
>> -			vcpu->arch.exception.nr = DF_VECTOR;
>> -			vcpu->arch.exception.error_code = 0;
>> -			return;
>> -		default:
>> -			/* replace previous exception with a new one in a hope
>> -			   that instruction re-execution will regenerate lost
>> -			   exception */
>> -			vcpu->arch.exception.pending = false;
>> -			break;
>>      
> When exceptions are handled serially previous exception have to be
> replaced by new one. Think about #PF during #DE. #PF should be handled first
> before #DE can proceed.
>    

"replacing" exceptions is dangerous in the case of debug exceptions and 
machine checks, since restarting execution won't recover them.


-- 
error compiling committee.c: too many arguments to function